Question: Omar has rowed his boat for a total of $21$ miles since he started rowing daily. He has been rowing $3$ miles each day. For how many days has Omar been rowing?
Explanation: The number of days that Omar has been rowing is the total number of miles rowed divided by the number of miles rowed each day. $21\text{ miles} \div 3\text{ miles per day} = \text{number of days rowing}$ $21\text{ miles} \div 3\text{ miles per day} = 7\text{ days}$